package com.codefarmer.practice.config;

import com.alibaba.fastjson.JSON;
import com.codefarmer.practice.annotation.AccessLimit;
import com.codefarmer.practice.utile.Ipsettings;
import com.codefarmer.practice.utile.RedisUtils;

import org.apache.commons.lang3.StringUtils;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.OutputStream;

/**
 * 定义拦截器
 * @Author codefarmer_z
 * @Date 2022/4/8 22:36
 * @Version 1.0
 */

public class FangshuaInterceptor extends HandlerInterceptorAdapter {
    private RedisUtils redisUtils;

    public FangshuaInterceptor(RedisUtils redisUtils) {
        this.redisUtils = redisUtils;
    }

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        //判断请求是否属于方法的请求
        if (handler instanceof HandlerMethod) {
            HandlerMethod hm = (HandlerMethod) handler;
            //获取方法中的注解,看是否有该注解
            AccessLimit accessLimit = hm.getMethodAnnotation(AccessLimit.class);
            if (accessLimit == null) {
                return true;
            }
            int seconds = accessLimit.seconds();
            int maxCount = accessLimit.maxCount();
            boolean login = accessLimit.needLogin();
            String remoteHost = Ipsettings.getRemoteHost(request);
            String key = "IP:" + remoteHost;
            //如果需要登录
            if (login) {
                //获取登录的session进行判断
                //.....
                key += "" + "1";  //这里假设用户是1,项目中是动态获取的userId
            }

            //从redis中获取用户访问的次数
            String s = redisUtils.get(key);
            Integer count = null;
            if (StringUtils.isNotBlank(s)) {
                count = Integer.valueOf(s);
            }

            if (s == null) {
                //第一次访问
                redisUtils.set(key, 1, seconds);
            } else if (count < maxCount) {
                //加1
                Long expire = redisUtils.getExpire(key);
                redisUtils.set(key, ++count,expire);
            } else {
                //超出访问次数
                this.render(response, "请求过于频繁~请稍后再试~"); //这里的CodeMsg是一个返回参数
                return false;
            }
        }

        return true;
    }
    private void render(HttpServletResponse response, String cm) throws Exception {
        response.setContentType("application/json;charset=UTF-8");
        OutputStream out = response.getOutputStream();
        String str = JSON.toJSONString(cm);
        out.write(str.getBytes("UTF-8"));
        out.flush();
        out.close();
    }
}
